Magnetic compass for current meters



Jan. 28, 1941. e. RATHKE MAGNETIC COMPASS FOR CURRENT METERS Filed Sept. 25, 1936 I I I I nnmmuufill entan- Patented Jan. 28, 1941 UNITED STATES MAGNETIC COMTPASS FOR. CURRENT METERS Gunther Rathke, Berlin-Wilmersdorf, Germany,

assignor to Askania-Werke A. G. vormals Centralwerkstatt Dessau und Carl Bamberg-Friedenau, a corporation of Germany Application September 25, 1936, Serial No. 102,601 In Germany September 25, 1935 2 Claims.

This invention relates to an instrument for measuring and recording the velocity and direc-- tion of a current in lakes, rivers, and oceans. For the determination of the direction of the current a compass is provided.

The principal object of this invention is to avoid any movement of the compass card which is free and rotatably mounted, by locking the same for the time of the recording-operation.

With this and other :objects in view the invention will be more fully hereinafter disclosed and particularly pointed out in the claims.

Referring now to the accompanying drawing in which an embodiment of the invention is shown by way of example:

The single figure of the drawing is an elevation of the compass card and means for looking it during the operation of the recording mechanism. The water current meter comprises an outer body or housing (not shown) suspended by means of a suspension rod from a cable. The suspension rod is rotatably mounted in said body or housing so as to enable the same to assume the direction of the'current by oscillating about the axis of the rod. In the outer body or housing are arranged the various measuring or indicating and recording devices as well as the driving and starting means. Thus the housing contains a compass having a compass card 24 mounted on a pin 25 for movement with great sensitivity, However, a force must be exerted on the card for recording the card indications from time to time. 'For this purpose, a locking device is provided in order to lock the card for the time of the recording operation. The locking device consists of a spherical cup 26 fixed to the lower side of the card, and of a second cup 21, to engage the first cup and hold the same against a stop thereby preventing a displacement. In the example shown the stop consists of three screws 28 adjustable on a. disc 29. The disc 29 is fastened to an arm 30 pivotally mounted at .3! on a frame i2 secured to the middle part of the outer body. The arm is normally held in the position shown in Figs. 1 and 2 by means :of a screw 33 and may be raised to remove the card from the pin 25 after removing a bearing 39' out of engagement with a shaft =66 later to be described.

The second cup 21 is fixed to a sleeve .34 yieldin ly guided between spring loaded rollers 35. An angle lever is pivoted at 3% one arm 31a of this lever cooperating with the lower end :of the sleeve 34 while its other arm 31b is in an engaging relation with any suitable means for rocking the angle lever. In case the recording operation has to take place at regular intervals, the angle lever 31a, 31b may be actuated for locking the compass card by a clockwork provided in the water current meter housing. As will be readily understood from the drawing, the mechanism described moves the sleeve upwardly and downwardly. In its upper position the card is opposite a recording hammer M which is adapted to press a suitable recording ribbon or strip 42 against the rim of the card provided with printing types 43. Preferably a metal foil is used as recording strip to Withstand moisture. A suitable pad or cushion 44 of rubber or the like, is arranged between the hammer and the strip or ribbon to prevent the hammer from damaging the strip or ribbon.

In order to reduce its weight, the card may be made of textile Bakelite the rim 24a cooperating with the hammer of any suitable metal.

The second cup 21 has apertures 21a so that the water may easily escape from between the cups.

In the embodiment shown, in addition to the compass card 24 a direction recording disc 45 is provided. This disc is adjusted so as to indicate the relative direction, while the compass card indicates the absolute direction of the current.

The direction disk 45 is rotatably carried by the arm 30 mentioned above. A bevel gear =63 engaging with another bevel gear 64 is connected to the disc. A rotation is transmitted to the gear 64 through a shaft 66. In case of angular movement of the outer body or housing relatively to the suspensionrod mentioned above, the rotary movement will be transmitted to the shaft 66 and thus to the direction disc 45.

What I claim is:

1. In a water current meter a compass card provided with printing type for recording the position of the card relative to said meter; a

pivot for sup-porting said card for tilting and turning movement; means for arresting said card during the recording operation, said arresting means including a semispherical member mounted on said card concentrically to its point of support, a cup movable in the direction of the axis of said pivot and having a cavity for receiving said semispherical member; and a stop for arresting the card upon movement by said cup.

2. In a water current meter a compass card provided with printing type for recording the position of the card relative to said meter; a pivot for supporting said card for tilting and turning movement; means for arresting said card during the recording operation, said arresting means including a semispherical member mounted on said card concentrically to its point of support, a cup movable in the direction of the axis of said pivot and having a cavity for receiving said semispherical member; and an adjustable three-point stop for arresting the card upon movement, by said cup.

GUNTI-IER RATHKE. 

